


With Their Blue Eyes, Their Love is Realized

by limitedinfinites



Category: Kuroshitsuji | Black Butler, Undertale (Video Game)
Genre: Aged up Ciel Phantomhive, Crossover, Crossover Pairings, M/M, Saniel
Language: English
Status: In-Progress
Published: 2019-01-26
Updated: 2019-01-26
Packaged: 2019-10-16 11:13:27
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,111
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17548616
Author URL: https://archiveofourown.org/users/limitedinfinites/pseuds/limitedinfinites
Summary: Ciel falls into the Underground, but that's not the only thing he falls for.





	With Their Blue Eyes, Their Love is Realized

**Author's Note:**

> Co-Creator's Instagram//@lordcielphantomgayy

Ciel had it with Sebastian, he had it with the contract. He wanted to escape, but the only way to get rid of the contract was to get rid of himself. If he didn’t, then Sebastian would eat his soul without his revenge being completed. That’s what he planned on doing. He decided to climb a tall mountain, one that he was sure Sebastian didn’t know about, Mount Ebott. He climbed the mountain and suddenly tripped, falling down a hole that he didn’t see. 

“Ah!’ he screamed. He lands on a pile of bones. “Ouch what the he-” Ciel jumps back in surprise when he realizes what his whole body touched. Ciel climbs to his feet and dusts himself off. “Where did these bones come from..?” He asks himself as he walked down the hall mindlessly.  
Time skip to when Ciel exits the ruins.

Ciel shivers as a cold gust of wind blow in his direction. ‘Why is it snowing?’ He wonders. He continues following a dirt path through the snow and faintly hears voices in the distance. Ciel crosses his arms over his chest to ease himself from the cold and he continues to follow the path until the voices get louder and louder. He can just make out what one of the voices was saying. 

“SANS! HAVE YOU FOUND A HUMAN YET?” the loud voice exclaimed. 

“nope.” a deeper voice says.

Ciel approaches them at a quickened pace to get some answers. Papyrus looks down at the small human. 

“SANS! WHAT IS THAT?” he asks. Sans looks up at his taller brother. 

“I don’t know.” 

Ciel raises an eyebrow as he watches the two skeletons talk to each other. Sans looks at the blue haired male, one of his eyes flashing blue for a split second. 

“hello. i’m Sans, Sans the skeleton.” He reaches out his hand and Ciel does the same and shook his hand. A slight spark was felt as their hands connected briefly. This startles Ciel and he quickly pulls his hand back. Sans gave Ciel a look of confusion, but is then replaced with a grin. The spark, there was no doubt about it. They were soulmates. While all this was going on, Papyrus looks at the two of them, more confused than Sans looked earlier. 

“WHAT IS GOING ON? I NEED TO CAPTURE THAT HUMAN. I WILL GO AND MAKE PUZZLES TO GET HIM.” And with that Papyrus walks away. 

Sans and Ciel stood in a momentary awkward silence before the young lord coughs.

“I would like to inquire where I am?”

Sans smirks and opens his arms to gesture around him.

“Welcome to the Underground.” Ciel took a step back from the skeleton. 

“How do I get out of here? I’m not about to stay here.” 

“don’t worry kiddo, i’ll help you out. but first, would you mind entertaining my brother a bit?” Sans asks. Ciel let out a heavy sigh. 

“I suppose if that’ll get me out of here, then fine.” He replies. He didn’t want to stay here any longer than he had to.  
“But, make it quick. I have business to attend to and it’s not here.” 

“it’s nothing too difficult, just a couple puzzles.” Sans winks and fazes out of existence. Ciel’s lone eye widened as Sans suddenly disappears. Where could he have gone? No matter. Ciel has to get out of here. He continues to follow the dirt path for a few minutes. He encounters a few monsters, but didn’t pay them any mind. Then he ran into Papyrus again. 

“THERE YOU ARE HUMAN! I HAVE PREPARED A GREAT PUZZLE FOR YOU! YOU WON’T GET PASSED IT!” It was a plate of spaghetti. Ciel refused to eat it. 

“WHAT!? HOW CAN YOU REFUSE SUCH A PERFECT PLATE OF PASTA?” Sans came out from behind Papyrus.

“I guess he just went PASTa your puzzle.” Papyrus gave Sans a dirty look. 

“SANS, NO MORE PUNS! WE’VE TALKED ABOUT THIS!” Sans chuckles and Papyrus left. 

“Don’t worry, only a few more puzzles left. I’m sure you’ll be fine.” Sans also walks away. 

A few more puzzles went by and Ciel finally exited the forest and made it to the quiet town of Snowdin. Yellow lights from the log houses brings relaxing vibes all around. Ciel slows down his pace to look at the beautiful scenery. He stops in front of a place called Grillbys. His stomach growled. He was hungry. It’s been a long time since he had something to eat. He should’ve eaten Papyrus’s pasta. He walks into the small restaurant. To his surprise, a familiar skeleton sat down at a stool behind the counter. Ciel walks over to the counter and sits down beside him without a word. 

“Hey kiddo.” Ciel looked at him. 

“Hey.” is all he said.

“You don’t talk much do ya?” Sans orders them both a plate of french fries. He doesn’t fancy french fries much because they were greasy, but Ciel was hungry, so he would eat it anyway. 

“I have no reason to talk to you.” Ciel replies, shrugging his shoulders. 

“Say, you must be tired.” Sans said. “Why don’t you come over to my place to rest for a bit? That way you’ll have enough energy to find your way out of here.” Ciel nibbled on a french fry before answering. 

“I mean, I guess. I am kind of tired.” He wasn’t sure how well he’d sleep at a skeleton’s house though. He feared he would have to share a whole ass coffin with one. Ciel shivered at the thought. 

While Ciel wondered about the home of a skeleton, Sans let his eyes wander over the young boy. He was shocked to have found his soulmate, let alone it being a human, but he wasn’t disappointed. After about ten minutes went by, Ciel finished his french fries. He was full now and was a lot more tired than before. 

“Let’s go now.” Ciel said, getting ready to jump off the stool. Sans got off of the stool first and he grabbed Ciel’s hand, helping him down from the stool. Ciel’s pale cheeks turned pink for a moment at the gesture, but he quickly pulled his hands away anyway. 

“I didn’t need your help with that.” Ciel said. 

“You’re welcome.” Sans winked and he led Ciel out of Grillbys and to his house. Fortunately, Papyrus wasn’t home. He must be meeting with Undyne or something. Sans wasn’t worried about it. He opened up the door, allowing Ciel to walk in first. The slightly younger male walked into the house. His blue eye scanned around the house. 

“Wow…” he says under his breath. 

“You can sleep on the couch.” Sans says. 

“I would prefer a bed.” Ciel replied. Sans smirks at this. 

“Oh sure, but I hope you don’t mind sharing.” He winks. Ciel blushes at the thought of sharing a bed with Sans. ‘Why is my heart beating so hard? He’s a skeleton.’ Ciel tries to come up with a response.

“lol i’m just kidding.” Sans turns and starts to walk up the stairs. “Come, i’ll show you my room.”

Ciel couldn’t understand this feeling. He had never felt it before. What was going on? He took a deep breath in and out, trying to calm himself down. He shook his head and wiped the blush off of his face. Ciel silently followed the skeleton of the stairs and to Sans’s bedroom. The skeleton opened up the bedroom to reveal a filthy room. 

“I want you to clean this before I sleep on this bed.” Ciel said, scrunching his nose. 

“Oh? It’s going to get dirtier soon, so why bother?” Sans winked. Ciel’s face flushed at the thought of what might go down before shaking his head. 

“W-What are you talking about?!? I won’t sleep until this bed is clean.” Ciel angrily exclaims. Sans smiles at the feistiness of the earl before snapping his fingers and making the whole mess go away. Ciel’s jaw dropped in awe as the mess suddenly disappeared. 

“W-What the hell? Skeletons can just… make things disappear like that?” Sans chuckled and shook his head. 

“Not EVERY skeleton.”

Ciel didn’t say anything after that. “I’m going to sleep now.” He says, sitting down on the now clean bed. 

“Alright, then I guess I’ll go now.” Sans says and turns around to leave. Out of nowhere, Ciel grabs Sans’s boney arm.

“Wait, stay. Stay here until I fall asleep.” Ciel has no idea where that came from, but all he knows is that he feels a warmth in his body whenever Sans is around. Sans smiles at Ciel’s cuteness and sits on the edge of the bed.

Ciel lays down on the bed and pulls the covers over his small body. The blanket was thin and didn’t keep him that warm, but he was too tired to notice. Sans stared down at Ciel, a warm smile on his face. He was glad about one thing at least, that this boy was his soulmate. Ciel’s eyes closed and his body started to relax. About an hour went by as Sans stared down at the sleeping boy. He was curious about what was under his eyepatch. Once he knew that Ciel was asleep, he reached down and untied the eyepatch, pulling it off. Ciel whined softly, was he waking up? His eyes slowly fluttered open. Sans’s hollow eye sockets widen as he saw the different colored eye. Ciel and Sans were very similar in the sense, they both had a secret eye. Why did Ciel hide it? Ciel’s tired bi-colored eyes looked up at Sans. 

“Mm, why are you staring at me?” Then he realized his eye patch was off and he jumped out of the bed. 

“S-Sans!? What the hell!?” He snatches the eye patch from the skeleton’s boney fingers and quickly ties it back on. 

“You will tell no one of what you saw!” Ciel stares down Sans, making sure he was getting the message across. 

“Under one condition.”

“What?”

“Kiss me.” Sans says, staring back at Ciel.

At those two words, Ciel’s pale complexion turned into a red one. His face was completely flustered. 

“K-Kiss you? What the hell are you playing at?” The young earl asks, averting his eyes, as he couldn’t look at the skeleton anymore. Why did those words embarrass him so?  
Sans took a step towards Ciel, carefully observing him. Ciel took a few steps back, though continuing to look at the skeleton, bewildered by his request. Sans proceeds on until he is right in front of Ciel. Ciel kept taking steps back until his back is pressed against the wall, his breath getting heavy. Sans slams his hands against the wall besides Ciel's head. 

“Kiss me.”

Ciel couldn’t think straight right now. His mind is going in many different directions. Did he want his secret to stay a secret? What if this guy was lying and he wouldn’t keep his secret even if he did kiss him? Ciel stared into the deep abysses which happened to be Sans’s eyes. He couldn’t look away, he didn’t want to look away. 

“J-Just this once.” He says softly before swallowing nervously. He sighed shakily and leaned forward. It was a good thing they were about the same height, so Ciel didn’t have to stand on his tiptoes or anything. He closed his eyes and his face got closer and closer to Sans. He puckered his lips, their lips being mere centimeters apart. Ciel hesitated a bit but Sans cupped his cheek and they soon connected. The moment they touched, it was like fireworks were set off. A buzz of electricity ran through their veins as they leaned further into the kiss. A shiver was sent up Ciel’s spine as their lips connected. What was this feeling? He didn’t know how to react to such a thing. To his own surprise, he kissed the skeleton back. It was an odd feeling since he had lips and, well, Sans didn’t. Nevertheless, it still made him feel alive, very alive.  
After a moment, Sans pulls away from the kiss. A chuckle passes his lips as he looked at the younger male. 

“Your secret’s safe with me,” is all he had to say. Ciel had almost forgotten about the whole secret thing. That’s why they were kissing. 

“R-Right.” He cleared his throat. “Anyways…” 

He moves away from Sans, a warmth still lingering on his lips. 

“Goodnight” he whispers.

“Goodnight kiddo,” Sans winks and walks out of the room. Ciel made his way back onto the bed, trying not to think too much of the skeleton before falling into a deep slumber.

**Author's Note:**

> Dedicated to my two best friends, detiny and arele, who love and support me always <3


End file.
